1. Field of the Invention
This invention relates to a power transmission shaft and a power transmission device using the same.
2. Description of the Related Art
A conventional power transmission device for a vehicle is described in, for example, Japanese Patent Laid-open Publication No. 2001-315539. The power transmission device includes an input shaft receiving a power from an engine, an intermediate shaft connected to the input shaft at one end thereof via a constant velocity joint, and an output shaft connected to the other end of the intermediate shaft via a constant velocity joint. Bellows-shaped boots are provided to cover a connecting portion between the constant velocity joints and the intermediate shaft respectively, so as to keep lubricant or the like within the constant velocity joints.
Around an outer circumference of the intermediate shaft, a boot-engaging groove is formed to fix the boots on the intermediate shaft. The boot has a protrusion on an inner circumference thereof to engage with the groove of the intermediate shaft. A clamp member is fixed on an outer circumference of the boot to urge the same onto a respective member. Thus, the intermediate shaft and the boot are mutually positioned in the axial direction while assuring sealing accuracy.
In the meanwhile, the boot-engaging groove of the conventional intermediate shaft is formed by a machining process. However, such a machining process for forming the groove may cause a problem of high cost.